Connectors comprising interfitting male and female connectors or connector housings are well-known in the art, and such connectors are commonly used for connecting electrical wire harnesses and similar apparatus. It is a problem with such connectors that they can inadvertently be pulled apart or separated during use, breaking the desired connection, electrical or otherwise. To overcome this problem, it has been suggested in the prior art to provide a locking mechanism on one of the connector housings such that when two complementary connector housings are interfitted, it is impossible, or at least very difficult, for them to be inadvertently pulled apart.
One method suggested by the prior art provides the male connector housing with a flexible locking arm projecting from the surface of the housing. The free end of the locking arm is provided with a beveled locking projection adapted to allow the male connector housing to be inserted into a female connector housing, the locking projection engaging a catch or shoulder in the female connector housing to prevent the connectors from being pulled apart. The fulcrum of the flexible locking arm corresponds to the juncture of the locking arm and the surface of the male housing, and the locking arm and locking projection lie above the fulcrum with respect to the housing. The distance between the fulcrum and an extension line of the locking projection running parallel to the locking arm creates a lever arm between the two.
A problem with this prior art locking mechanism is that, when the connector housings are pulled in opposite directions by a force tending to separate them, a moment equal to the magnitude of the force times the length of the lever arm acts upon the locking arm in a direction tending to disengage the locking projection from the catch or shoulder of the female housing. This defeats the purpose of the prior art locking mechanism, making it unsuitable for providing secure locking engagement between the connector housings.